The process of selecting teachers cannot screen all [the bad candidates] out, and there are nearly 400,000 teachers in Thailand, hence a large organisation like this is bound to have some bad apples," Narong said. "People who apply to be teachers don't show an inappropriate side while applying for the job but when they actually work and are exposed to temptations, some might do inappropriate things, and they must be probed and severely punished if found guilty," he said.